The proposed project is a systematic study of the effects of ethanol on the physical properties of a series of individual pure lipid membrane components and simple mixtures of components. The rationale for this approach is the evidence that alcohol interacts with the central nervous system by dissolving into the membrane lipids of neurons, altering their function. The broad objective of the study is to characterize ethanol-lipid interactions and to elucidate the role of membrane lipid composition in ethanol intoxication, tolerancy and dependency. The effect of pentobarbital on these ethanol effects will also be investigated, in order to elucidate the cross reactivity of alcohol and barbiturates. The physical properties to be measured are lipid fluidity, lipid phase transitions, and ethanol membrane solubility. The methods to be used are fluorescence depolarization and absorption spectrophotometry. The pure membrane components to be studied are a series of phosphatidylcholines, phosphatidylethanolamines, and cholesterol. The lipid combinations to be studied are binary mixtures of the phospholipids and mixtures of phospholipid and cholesterol. The results will be interpreted from the point of view of existing theories of general anesthesia. The significance of this research to human health is that it will provide insight into the mechanisms of alcoholism, particularly with respect to intoxication, tolerancy and dependency, and cross reactivity with barbiturates. The results will be useful in suggesting therapeutic measures for use during withdrawal from alcohol dependency, and may also suggest some diagnostic criteria for identifying individuals with a predisposition to alcoholism. These results will also provide insight into mechanisms of general anesthesia.